Treating myself as a writer, option 1: Write stories that give me an excuse to play a de-aged Thor big-brothering an adult Loki. Naturally Loki melts for it and is wildly protective.--
Avengers Tower, Christmas.--
Tony: You didn't get anyone a gift? Even Thor?
Loki: We do not celebrate your trite little 'holiday'.
Tony: Yeah, okay, bah humbug to you too, Scrooge.
[Bruce and Little Thor enter]
Little Thor: [runs straight for Loki with a grin, hiding something behind his back] Hi, brother.
Loki: [lifts a brow] Hello, brother...[sees an impatient, expectant expression on Thor's face. Humors him.] What have you got there?
Little Thor: [delighted to be asked, produces a green and red wrapped box] Merry Christmas Eve, Loki!
Little Thor: You get a present tonight, and the rest tomorrow?
Tony: Not as many as you got Thor though, right? Since he's your one and only brother. It's not like you didn't get him anything...cause that would be, phew...heart-breaking. [Feigns emotional blow]
Loki: [glaring daggers over Thor's head]
Little Thor: Open it, brother!
Loki: [obliges, it's a soft, deep green scarf with a little light green snake] Oh...brother this...
Little Thor: Do you like it?! Here, I will help you. [Proceeds to put it on and then pats it on Loki's chest while beaming] You love green and snakes.
Loki: [swallows hard] Indeed I do...thank you for this, brother...I ah...thought I was supposed to give you all of -your- presents tomorrow...is that all right?
Little Thor: Yeah! We can open them together!
Tony: [smirking intensely at Loki]
[The biggest pile of presents ever seen by any Avenger]
Tony: You're such a sucker.
Little Thor: [settles in against Loki's side as they each drink a mug of cocoa]
Loki: [arm around Thor, palm splayed on his stomach affectionately].
Little Thor: [In his new matching red scarf] Merry Christmas, little brother. I love you.
Loki: [Would start Ragnarok for baby Thor in a heartbeat] I love you too, brother. [Kisses his head].
Tony: The best part is, Jarvis is always recording-